This proposal presents a series of laboratory studies designed to answer questions concerning the role of psychosocial factors in the development of hypertension and related cardiovascular disease. Four studies are proposed. The first 3 focus on effects of active coping and social support in normotensive and borderline hypertensive subjects. Study 4 is concerned with a possible cause of White Coat Hypertension. Studies 1-3 follow up our findings which show that ability to cope reduces blood pressure and heart rate reactivity, when the effortfulness of the task is controlled. Many studies show that ability to cope increases reactivity; however, in those studies effort co-varies with the enhanced control due to availability of a coping response. Studies 1 and 2 test the proposition that active coping is a function of (at least) 2 separate components--enhanced control and effortfulness--which we hypothesize have opposite effects on reactivity. In addition, we test the proposition that social support represents a special case of ability to cope, and therefore may exert its reactivity-reducing effects because of its control-enhancing aspects, as would other available coping responses. In addition, we propose that reactivity differences between normotensive and borderline hypertensive populations can be better understood when differences in the response to each of the components of active coping--enhanced control and effort--are examined individually. In Study 4, we propose to follow up on pilot data in which we have observed that a proportion of young normotensives show an anticipatory rise in blood pressure (taken using a finger-cuff attached to a Finapres Monitor), prior to the entry into the room of an MD. We hypothesize that these anticipatory responses are (1) related to the subject's history of medical experiences; (2) related to the White Coat response seen in older patients; and (3) is not simply an instance of generalized reactivity. In order to test these propositions, we propose to examine the subjects in the laboratory (in order to determine anticipator status, and perform general reactivity tests) as well as in the medical clinic, where responses to the MD can be observed.